The present invention relates to cylinders employed on a press as part of the press assembly for printing, embossing, punching or otherwise marking web or sheet material fed through the press. The invention has particular application to printing cylinders, although it is not limited thereto. In general, the invention pertains to press cylinders of the type having removable printing plates mounted to a support cylinder.
A known type of printing plate is made of a thin flexible material which is adhesively mounted on a printing cylinder. When it is desired to change a portion of the print type it is necessary to remove the flexible printing plate, or selected portions thereof, and replace it with the new printing plate material. To accomplish this, many known printing cylinders require removal of the printing plate or sections, realignment of the new sections of the plate on the cylinder, and re-adhesion onto the cylinder. The process is time consuming and often results in inadvertent damaging of the printing plate or portions of it.
In general, the prior art discloses the concept of providing a flexible printing plate attached to a printing cylinder. Such prior art devices usually involve a thin, flexible plate to which is affixed, on the underside thereof, locking bars or wedges adapted to be received within a groove or otherwise attached to means provided on the cylinder. Such devices usually involve rather complex plate locking members and cylinder fastening and aligning devices. The plates are of course subjected to considerable centrifugal forces by rotation of the press cylinder and to other stresses during printing, and so must be securely mounted.
For example, U.S. Pat. Nos. 1,503,074; 3,152,544; and 3,603,256 each show different mounting means for mounting printing plates to a cylinder form. Each of these prior patents shows fairly complex securing means which are relatively expensive to manufacture and possibly not feasible in relatively small cylinders, such as on presses used to print labels, etc.
It is an object of the present invention to overcome the problems and shortcomings of prior art devices and to provide a novel press cylinder or assembly including simple and efficient means for removably mounting saddle members to a support cylinder.
It is another object of the present invention to provide a simple snap-on, snap-off type mounting which removably yet securely affixes saddle members carrying print type or other marking means to a support cylinder.
It is yet another object of the present invention to provide a press cylinder assembly in which a selected one or more of such saddle members may be removed and replaced on a support cylinder to permit replacement of selected portions of a printing or other marking cylinder.